Methods for forming a transition metal niobium nitride film on a substrate by atomic layer deposition and related semiconductor device structures

ABSTRACT

Methods for forming a transition metal niobium nitride film on a substrate by atomic layer deposition and related semiconductor device structures are provided. In some embodiments methods may include contacting a substrate with a first reactant comprising a transition metal precursor, contacting the substrate with a second reactant comprising a niobium precursor and contacting the substrate with a third reactant comprising a nitrogen precursor. In some embodiments related semiconductor device structures may include a semiconductor body and an electrode comprising a transition metal niobium nitride disposed over the semiconductor body.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Divisional of, and claims priority to and thebenefit of, U.S. patent application Ser. No. 15/795,056, filed Oct. 26,2017 and entitled “METHODS FOR FORMING A TRANSITION METAL NIOBIUMNITRIDE FILM ON A SUBSTRATE BY ATOMIC LAYER DEPOSITION AND RELATEDSEMICONDUCTOR DEVICE STRUCTURES,” which claims priority to U.S.Provisional Patent Application Ser. No. 62/415,828, filed Nov. 1, 2016,the disclosures of which are hereby incorporated by reference herein.

BACKGROUND Field of the Invention

The present disclosure relates generally to methods for forming atransition metal niobium nitride film on a substrate by atomic layerdeposition and related semiconductor device structures.

Description of the Related Art

Metal-oxide-semiconductor (MOS) technology has conventionally utilizedn-type doped polysilicon as the gate electrode material. However, dopedpolysilicon may not be an ideal gate electrode material for advancednode applications. For example, although doped polysilicon isconductive, there may still be a surface region which can be depleted ofcarriers under bias conditions. This region may appear as an extra gateinsulator thickness, commonly referred to as gate depletion, and maycontribute to the equivalent oxide thickness. While the gate depletionregion may be thin, on the order of a few angstroms (A), it may becomesignificant as the gate oxide thicknesses are reduced in advance nodeapplications. As a further example, polysilicon does not exhibit anideal effective work function (eWF) for both NMOS and PMOS devices. Toovercome the non-ideal effective work function of doped polysilicon, athreshold voltage adjustment implantation may be utilized. However, asdevice geometries reduce in advanced node applications, the thresholdvoltage adjustment implantation processes may become increasinglycomplex and impractical.

To overcome the problems associated with doped polysilicon gateelectrodes, the non-ideal doped polysilicon gate material may bereplaced with an alternative material, such as, for example, atransition metal nitride. For example, a transition metal nitride may beutilized to provide a gate electrode structure with a more idealeffective work function for both the NMOS and PMOS devices, where theeffective work function of the gate electrode structure, i.e., theenergy needed to extract an electron, must be compatible with thebarrier height of the semiconductor material. For example, in the caseof PMOS devices, the required effective work function is approximately5.0 eV.

In addition, memory cell size has continuously decreased as the designrule of dynamic random access memory (DRAM) has decreased. Accordingly,the height of a capacitor, associated with the DRAM, has continuouslyincreased and the thickness has become smaller in order to maintain adesired charge capacitance. The height of the capacitor has increasedand the thickness of the capacitor has decreased because the chargecapacitance is proportionate to the surface area of an electrode and thedielectric constant of a dielectric layer, and is inverselyproportionate to the distance between the electrodes, i.e., thethickness of the dielectric layer. The high aspect ratio of thecapacitor may cause “leaning” and this “leaning” may be variableaccording to the properties and/or thickness of the electrode comprisingthe capacitor. For example, DRAM capacitors comprising titanium nitrideas an electrode material may lean when the aspect ratio of the capacitoris greater than approximately 15:1. Therefore alternative materials maybe desirable for the DRAM capacitor electrodes to prevent leaning ofarrays of capacitors (storage nodes) and the associated device failureresulting from leaning device structures.

Atomic layer deposition (ALD) may be utilized for the deposition oftransition metal nitride films, such as, for example, tantalum nitride(TaN), titanium nitride (TiN), tungsten nitride (WN) and niobium nitride(NbN). However, the electronic, crystallographic and physical propertiesof known ALD transition metal nitride films may be limited and novel ALDtransition metal nitride films may be desirable.

SUMMARY

This summary is provided to introduce a selection of concepts in asimplified form. These concepts are described in further detail in thedetailed description of example embodiments of the disclosure below.This summary is not intended to identify key features or essentialfeatures of the claimed subject matter, nor is it intended to be used tolimit the scope of the claimed subject matter.

In some embodiments, methods for forming a transition metal niobiumnitride film on a substrate by atomic layer deposition are provided. Themethods may comprise contacting the substrate with a first reactantcomprising a transition metal precursor, contacting the substrate with asecond reactant comprising a niobium precursor, and contacting thesubstrate with a third reactant comprising a nitrogen precursor.

In some embodiments, semiconductor device structures are provided. Thesemiconductor device structures may comprise a semiconductor body and anelectrode comprising a transition metal niobium nitride disposed overthe semiconductor body.

For the purposes of summarizing the invention and the advantagesachieved over the prior art, certain objects and advantages of theinvention have been described herein above. Of course, it is to beunderstood that not necessarily all such objects or advantages may beachieved in accordance with any particular embodiment of the invention.Thus, for example, those skilled in the art will recognize that theinvention may be embodied or carried out in a manner that achieves oroptimizes one advantage or group of advantages as taught or suggestedherein without necessarily achieving other objects or advantages as maybe taught or suggested herein.

All of these embodiments are intended to be within the scope of theinvention herein disclosed. These and other embodiments will becomereadily apparent to those skilled in the art from the following detaileddescription of certain embodiments having reference to the attachedfigures, the invention not being limited to any particular embodiment(s)disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS

While the specification concludes with claims particularly pointing outand distinctly claiming what are regarded as embodiments of theinvention, the advantages of embodiments of the disclosure may be morereadily ascertained from the description of certain examples ofembodiments of the disclosure when read in conjunction with theaccompanying drawings, in which:

FIG. 1 illustrates an example of a process for forming a transitionmetal niobium nitride according to the embodiments of the disclosure;

FIG. 2 illustrates an example of a process for forming a transitionmetal niobium nitride according to additional embodiments of thedisclosure;

FIG. 3 schematically illustrates a semiconductor device structurecomprising a PMOS transistor according to the embodiments of thedisclosure;

FIG. 4 schematically illustrates a semiconductor device structurecomprising a DRAM capacitor according to embodiments of the disclosure;

FIG. 5 schematically illustrates a partially fabricated semiconductordevice structure comprising transition metal niobium nitride layersdeposited according to the embodiments of the disclosure;

FIG. 6 schematically illustrates a reaction system configured to performthe embodiments of the disclosure.

DETAILED DESCRIPTION

The illustrations presented herein are not meant to be an actual view ofany particular material, structure, or device, but are merely idealizedrepresentations that are used to describe embodiments of the disclosure.

As used herein, the term “atomic layer deposition” (ALD) may refer to avapor deposition process in which deposition cycles, preferably aplurality of consecutive deposition cycles, are conducted in a processchamber. Typically, during each cycle the precursor is chemisorbed to adeposition surface (e.g., a substrate surface or a previously depositedunderlying surface such as material from a previous ALD cycle), forminga monolayer or sub-monolayer that does not readily react with additionalprecursor (i.e., a self-limiting reaction). Thereafter, if necessary, areactant (e.g., another precursor or reaction gas) may subsequently beintroduced into the process chamber for use in converting thechemisorbed precursor to the desired material on the deposition surface.Typically, this reactant is capable of further reaction with theprecursor. Further, purging steps may also be utilized during each cycleto remove excess precursor from the process chamber and/or remove excessreactant and/or reaction byproducts from the process chamber afterconversion of the chemisorbed precursor. Further, the term “atomic layerdeposition,” as used herein, is also meant to include processesdesignated by related terms such as, “chemical vapor atomic layerdeposition”, “atomic layer epitaxy” (ALE), molecular beam epitaxy (MBE),gas source MBE, or organometallic MBE, and chemical beam epitaxy whenperformed with alternating pulses of precursor composition(s), reactivegas, and purge (e.g., inert carrier) gas.

As used herein, the term “substrate” may refer to any underlyingmaterial or materials that may be used, or upon which a device, acircuit or a film may be formed.

The present disclosure includes methods and device structures that maybe used to form a transition metal niobium nitride film or comprise atransition metal niobium nitride film. The existing ALD transition metalnitride films may have limitations due to their inability to tunecertain characteristics of the ALD transition metal nitride film; suchcharacteristics may comprise the effective work function, the electricalresistivity, the density, and the Young's modulus.

For example, it is known that the effective work function of a gateelectrode structure may vary as a function of its thickness, i.e., theeffective work function of the gate electrode structure may decrease orincrease with decreasing thickness of the materials comprising the gateelectrode. As device geometries decrease in advanced node applications,the thickness of the corresponding device films, for example, such asthe gate electrode, may also decrease with a corresponding change in theeffective work function of the film. Such a change in the effective workfunction of the gate electrode at reduced thickness may result in anon-ideal effective work function for NMOS and PMOS device structures.In addition, it also known that the properties of the conductivematerials comprising common DRAM capacitor electrodes may be non-idealin terms of mechanical strength and oxidation resistance. Methods andstructures are therefore required to provide a more desirable transitionmetal nitride film. Examples of such methods and structures aredisclosed in further detail below.

ALD is based on typically self-limiting reactions, whereby sequentialand alternating pulses of reactants are used to deposit about one atomic(or molecular) monolayer of material per deposition cycle. Thedeposition conditions and precursors are typically selected to provideself-saturating reactions, such that an adsorbed layer of one reactantleaves a surface termination that is non-reactive with the gas phasereactants of the same reactant. The substrate is subsequently contactedwith a different reactant that reacts with the previous termination toenable continued deposition. Thus, each cycle of alternated pulsestypically leaves no more than about one monolayer of the desiredmaterial. However, as mentioned above, the skilled artisan willrecognize that in one or more ALD cycles more than one monolayer ofmaterial may be deposited, for example if some gas phase reactions occurdespite the alternating nature of the process.

In some embodiments of the disclosure, an ALD-type process fordepositing transition metal niobium nitride films may be illustratedwith reference to FIG. 1 which illustrates non-limiting example ALD-typeprocess 100. After initial surface termination, if necessary or desired,the ALD pulse sequence may begin at step 102. The ALD-type process 100may then proceed with at least one deposition cycle which may comprise,contacting the substrate with a first reactant 104, contacting thesubstrate with a second reactant 106 and contacting the substrate with athird reactant 108. Once the first, second and third reactants have beenexposed to the substrate the deposition cycle may be repeated 108 untila predetermined thickness of transition metal niobium nitride isachieved 110. When the desired predetermined thickness of transitionmetal niobium nitride is achieved the deposition cycle is terminated andthe process may exit 112.

In some embodiments the ALD-type process 100 for depositing transitionmetal niobium nitride, may comprise at least one deposition cyclewherein the at least one deposition cycle may comprise, exposing thesubstrate to the first reactant, removing any unreacted first reactantand reaction by products from the reaction space, exposing the substrateto the second reactant, followed by a second removal step, and exposingthe substrate to the third reactant, followed by a third removal step.

In some embodiments the ALD-type process 100 for depositing transitionmetal niobium nitride, may comprise at least one deposition cyclewherein the at least one deposition cycle may comprise, exposing thesubstrate to the first reactant, exposing the substrate to the secondreactant, removing any unreacted first reactant and second reactant andreaction by products, and exposing the substrate to the third reactant,followed by a second removal step.

In some embodiments the ALD-type process for depositing transition metalniobium nitride, may comprise at least one deposition cycle wherein theat least one deposition cycle may comprise, exposing the substrate tothe second reactant, removing any unreacted second reactant and reactionby products from the reaction space, exposing the substrate to a firstreactant, followed by a second removal step, and exposing the substrateto the third reactant, followed by a third removal step.

In addition, it should be appreciated that in some embodiments, eachcontacting step may be repeated one or more times prior to advancing onto the subsequent processing step, i.e., prior to the subsequentcontacting step or removal/purge step.

In some embodiments, the first reactant may comprise a metal precursor,in particular a transition metal precursor. The transition metalprecursor or compound may comprise at least one of the transition metalsselected from the group comprising, scandium (Sc), yttrium (Y), titanium(Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum(Ta), chromium (Cr), molybdenum (Mo), tungsten (W), manganese (Mn),technetium (Tc), rhenium (Re), iron (Fe), ruthenium (Ru), osmium (Os),cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd),platinum (Pt), copper (Cu), silver (Ag), gold (Au), zinc (Zn), cadmium(Cd) and mercury (Hg).

As a non-limiting example embodiment, a transition metal halidereactant, such as, e.g., titanium tetrachloride (TiCl₄), may be used asthe transition metal precursor in ALD processes.

In some embodiments, the second reactant may comprise a niobiumprecursor and in some embodiments methods may comprise selecting theniobium precursor to comprise at least one of niobium pentachloride(NbCl₅), niobium pentafluoride (NbF₅), niobium pentaboride (NbB₅),niobium pentaiodide (NbI₅) and niobium pentabromide (NbBr₅).

In some embodiments, the third reactant may comprise a nitrogenprecursor and in some embodiments methods may comprise selecting thenitrogen precursor to comprise at least one of ammonia (NH₃), ammoniasalts, hydrogen azide (HN₃), alkyl derivatives of hydrogen azide,hydrazine (N₂H₄), hydrazine salts, alkyl derivatives of hydrazine,nitrogen fluoride (NF₃), and plasma-excited species of nitrogen (N₂).

Precursors may be separated by inert gases, such as argon (Ar) ornitrogen (N₂), to prevent gas-phase reactions between reactants andenable self-saturating surface reactions. In some embodiments, however,the substrate may be moved to separately contact a first transitionmetal reactant, a second niobium reactant and a third nitrogen reactant.Because the reactions self-saturate, strict temperature control of thesubstrates and precise dosage control of the precursors is not usuallyrequired. However, the substrate temperature may be such that anincident gas species does not condense into monolayers nor decompose onthe surface. Surplus chemicals and reaction byproducts, if any, areremoved from the substrate surface, such as by purging the reactionspace or by moving the substrate, before the substrate is contacted withthe next reactive chemical. Undesired gaseous molecules can beeffectively expelled from a reaction space with the help of an inertpurging gas. A vacuum pump may be used to assist in the purging.

According to some embodiments, ALD-type processes are used to formtransition metal niobium nitride films, for example, titanium niobiumnitride films on a substrate, such as an integrated circuit workpiece.Each ALD cycle may comprise three distinct deposition steps or phases.In a first phase of the deposition cycle (“the transition metal phase”),the substrate surface on which deposition is desired is contacted with afirst reactant comprising a transition metal such as titanium (i.e.,titanium source material or chemical) which chemisorbs onto thesubstrate surface, forming no more than about one monolayer of reactantspecies on the surface of the substrate.

In some embodiments, the transition metal (e.g., titanium) sourcechemical, also referred to herein as the “transition metal compound” (orin some embodiments as the “titanium compound”), is a halide and theadsorbed monolayer is terminated with halogen ligands. In someembodiments, the titanium halide may be titanium tetrachloride (TiCl₄).

In some embodiments, excess transition metal (e.g., titanium, tantalumor tungsten) source material and reaction byproducts (if any) may beremoved from the substrate surface, e.g., by purging with an inert gas.Excess transition metal source material and any reaction byproducts maybe removed with the aid of a vacuum generated by a pumping system.

In a second phase of the deposition cycle (“the niobium phase”), thesubstrate is contacted with a niobium precursor. In some embodiments theniobium precursor may comprise at least one of niobium pentachloride(NbCl₅), niobium pentafluoride (NbF₅), niobium pentaboride (NbB₅),niobium pentaiodide (NbI₅) and niobium pentabromide (NbBr₅).

The second niobium reactant may absorb on the substrate surface byeither insertion or displacement of the titanium-containing moleculesleft on the substrate surface. The substrate surface therefore comprisesa mixture of metal-containing molecules left on the substrate surface,the substrate surface comprising a mixture of transition metal species(e.g., titanium) and niobium species.

In some embodiments, excess second source chemical and reactionbyproducts, if any, are removed from the substrate surface, for exampleby a purging gas pulse and/or vacuum generated by a pumping system.Purging gas is preferably any inert gas, such as, without limitation,argon (Ar), nitrogen (N₂) or helium (He). A phase is generallyconsidered to immediately follow another phase if a purge (i.e., purginggas pulse) or other reactant removal step intervenes.

In a third phase of the deposition cycle (“the nitrogen phase”), thesubstrate is contacted with a nitrogen precursor. In some embodimentsthe nitrogen precursor may comprise at least one of ammonia (NH₃),ammonia salts, hydrogen azide (HN₃), alkyl derivatives of hydrogenazide, hydrazine (N₂H₄), hydrazine salts, alkyl derivatives of hydrazine(e.g., tertbutylhydrazine (C₄H₉N₂H₃), methylhydrazine (CH₃NHNH₂),dimethylhydrazine ((CH₃)₂N₂H₂)) nitrogen fluoride (NF₃) andplasma-excited species of nitrogen (N₂).

The third reactant, comprising a nitrogen precursor, may react with thetitanium and niobium containing molecules left on the substrate surface.Preferably, in the third phase nitrogen is incorporated into the film bythe interaction of the third nitrogen containing reactant with themonolayer left by the transition metal (e.g., titanium) source materialand the niobium source material. In some embodiments, reaction betweenthe third nitrogen containing precursors and the chemisorbed transitionmetal and niobium species produces a transition metal niobium nitridethin film over the substrate.

In some embodiments, excess third source chemical and reactionbyproducts, if any, are removed from the substrate surface, for exampleby a purging gas pulse and/or vacuum generated by a pumping system.Purging gas may be any inert gas, such as, without limitation, argon(Ar), nitrogen (N₂) or helium (He). A phase is generally considered toimmediately follow another phase if a purge (i.e., purging gas pulse) orother reactant removal step intervenes.

In some embodiments, the ALD-process of process 100 may comprise aplasma enhanced atomic layer deposition (PEALD) process. In suchembodiments the third reactant may comprise a nitrogen precursor and mayfurther comprise a plasma excited species of nitrogen (N₂). In someembodiments, the thirds reactant may comprise a nitrogen precursor andmay further comprise a plasma excited species of any reactant includinga nitrogen component. In some embodiments the third reactant, e.g., aplasma excited species of nitrogen (N₂), may be supplied to thesubstrate with the addition of further plasma excited species, such asplasma excited species of hydrogen (H₂).

In embodiments wherein the ALD-process comprises a plasma enhancedatomic layer deposition process utilizing plasma excited species, thesubstrate temperature during deposition may comprise a temperature ofbetween approximately 250° C. and approximately 400° C. In embodimentswhere in the ALD-process comprises a thermal atomic layer depositionprocess, i.e., an absence of plasma excited species, the substratetemperature during deposition may comprise a temperature of betweenapproximately 350° C. and approximately 450° C.

In some embodiments, a transition metal niobium nitride film formedaccording to one or more processes described herein is not ananolaminate film. That is, separate and distinct layers may not bevisible within the transition metal niobium nitride film. For example, acontinuous or substantially continuous transition metal niobium nitridefilm may be formed.

The deposition rate of the thin film by ALD, which is typicallypresented as Å/pulsing cycle, depends on a number of factors including,for example, on the number of available reactive surface sites or activesites on the surface and bulkiness of the chemisorbing molecules. Insome embodiments, the deposition rate of such films may range from about0.3 to about 5.0 Å/pulsing cycle. In some embodiments, the depositionrate can be about 0.3, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0Å/pulsing cycle.

In some embodiments of the disclosure, an ALD-type process fordepositing transition metal niobium nitride films may be illustratedwith reference to FIG. 2 which illustrates non-limiting example process200. After initial surface termination, if necessary or desired, the ALDpulse sequence may begin at step 202. The ALD-type process 200 may thenproceed with at least one complete deposition cycle 203.

In some embodiments, a process of depositing a transition metal niobiumnitride film comprises both a deposition process for depositing atransition metal nitride component (e.g., a number of deposition cyclesfor depositing a transition metal nitride, such as a number oftransition metal nitride sub-cycles), and a deposition process foradding a niobium component to the growing film (e.g., a number ofdeposition cycles which includes a precursor comprising niobium, such asa number of niobium nitride sub-cycles). For example, a process forfabricating a transition metal niobium nitride film may include a numberof complete deposition cycles, each complete deposition cycle includinga number of transition metal nitride sub-cycles and a number of niobiumnitride sub-cycles.

In some embodiments, a process of fabricating a transition metal niobiumnitride film having desired characteristics can include a number ofcomplete deposition cycles, where each complete deposition cycleincludes a ratio of a number of transition metal nitride sub-cycles to anumber of niobium nitride sub-cycles optimized to obtain the desiredcharacteristics, such as, for example, Young's modulus, density,stoichiometry, electrical resistivity and crystallographic orientation.The ratio of the number of transition metal nitride sub-cycles to thenumber of niobium nitride sub-cycles of a complete deposition cycle canbe expressed as having a percentage of niobium nitride sub-cycles (e.g.,a niobium nitride sub-cycle percentage or a niobium nitride depositionsub-cycle percentage). For example, a complete deposition cycle fordepositing a transition metal niobium nitride film including onedeposition cycle for depositing a transition metal nitride component(e.g., one transition metal nitride sub-cycle) and four depositioncycles for adding a niobium component (e.g., four niobium nitridesub-cycles) can have a niobium nitride sub-cycle percentage of about80%. In some embodiments, a complete deposition cycle can have a niobiumnitride sub-cycle percentage of about 10% to about 100%, including about25% to about 98%, about 50% to about 95%, and about 75% to about 85%.

In some embodiments, one or more parameters of a transition metalnitride sub-cycle can be different from that of another transition metalnitride sub-cycle. In some embodiments, one or more parameters of atransition metal nitride sub-cycle can be similar to or the same as thatof another transition metal nitride sub-cycle such that the transitionmetal nitride sub-cycles are performed under similar or identicalprocess conditions.

In some embodiments, one or more parameters of a niobium nitridesub-cycle can be different from that of another niobium nitridesub-cycle. In some embodiments, one or more parameters of a niobiumnitride sub-cycle can be similar to or the same as that of anotherniobium nitride sub-cycle such that the niobium nitride sub-cycles areperformed under similar or even identical process conditions.

In some embodiments, a transition metal niobium nitride film formedaccording to one or more processes described herein is a nanolaminatefilm. That is, separate and distinct layers may be visible within thetransition metal niobium nitride film. For example, the transition metalniobium nitride film may comprise a nanolaminate and may furthercomprise at least one layer of a transition metal nitride and at leastone layer of a niobium nitride.

In some embodiments, a transition metal niobium nitride film formedaccording to one or more processes described herein is not ananolaminate film. That is, separate and distinct layers may not bevisible within the transition metal niobium nitride film. For example, acontinuous or substantially continuous transition metal niobium nitridefilm may be formed.

As described above, in some embodiments, a process for forming atransition metal niobium nitride film of a desired thickness and/orcomposition can include an ALD deposition process (e.g., a transitionmetal nitride deposition sub-cycle and/or a niobium nitride depositionsub-cycle can comprise an ALD process). ALD type processes are based oncontrolled surface reactions that are typically self-limiting. Gas phasereactions are avoided by contacting the substrate alternately andsequentially with precursors, although in some instances, some overlapis possible. Vapor phase precursors are separated from each other in thereaction chamber, for example, by removing excess precursors and/orprecursor byproducts from the reaction chamber between precursor pulses.For example, an ALD deposition process can include contacting asubstrate with a first reactant (e.g., a transition metal precursor fora transition metal nitride deposition sub-cycle) and a second reactantcomprising niobium for a niobium nitride deposition sub-cycle such thatthe first and/or the second reactant adsorbs onto the substrate surface,and contacting the substrate with a third reactant (e.g., a nitrogenprecursor of a transition metal nitride deposition sub-cycle or anitrogen precursor of a niobium nitride deposition sub-cycle). Exposureof the substrate to the first precursor, the second precursor and thethird precursor may be repeated as many times as required to achieve afilm of a desired thickness and composition. Excess precursors may beremoved from the vicinity of the substrate, for example by evacuatingthe reaction chamber and/or purging from the reaction space with aninert gas, after each contacting step. For example, excess reactantsand/or reaction byproducts may be removed from the reactor chamberbetween precursor pulses by drawing a vacuum on the reaction chamber toevacuate excess reactants and/or reaction byproducts. In someembodiments, the reaction chamber may be purged between precursorpulses. The flow rate and time of each precursor, is tunable, as is thepurge step, allowing for control of the dopant concentration and depthprofile in the film.

Each cycle of an ALD process can include at least two distinct processesor phases. The provision and removal of a precursor from the reactionspace may be considered a phase. In a first process or phase of an ALDprocess, of a transition metal nitride deposition sub-cycle, forexample, a first precursor comprising a transition metal is provided andforms no more than about one monolayer on the substrate surface. Thisprecursor is also referred to herein as “the transition metal precursor”or “transition metal reactant.” In a second process or phase of the ALDprocess of a transition metal nitride deposition sub-cycle, for example,a third precursor comprising a nitrogen-containing compound is providedand reacts with the adsorbed transition metal precursor to form atransition metal nitride. This third precursor may also be referred toas a “nitrogen precursor” or “nitrogen reactant.” As described herein,the third precursor may comprise ammonia (NH₃) and/or another suitablenitrogen-containing compound that is able to react with the adsorbedfirst reactant under the process conditions. Preferably the reactionleaves a termination that is further reactive with the first precursoror another precursor for a different phase.

Additional processes or phases may be added and phases may be removed asdesired to adjust the composition of the final transition metal niobiumnitride film. In some embodiments, the additional processes or phasescan include one or more precursors different from that of the first andsecond process or phase. For example, one or more additional precursorscan be provided in the additional processes or phases. In someembodiments, the additional processes or phases can have similar oridentical process conditions as that of the first and second process orphase. In some embodiments, for a transition metal nitride depositionsub-cycle, one or more deposition sub-cycles typically begins withprovision of the transition metal precursor followed by the nitrogenprecursor. In some embodiments, one or more deposition sub-cycles beginswith provision of the nitrogen precursor followed by the transitionmetal precursor. One or more of the precursors may be provided with theaid of a carrier gas, such as nitrogen (N₂), argon (Ar) and/or helium(He). In some embodiments, the carrier gas may comprise another inertgas.

In some embodiments, in a first process or phase of an ALD process of aniobium nitride deposition sub-cycle, for example, a second precursorcomprising niobium is provided and forms no more than about onemonolayer on the substrate surface. This precursor is also referred toherein as “the precursor comprising niobium” or “the reactant comprisingniobium.” In a second process or phase of the ALD process of a niobiumnitride deposition sub-cycle, for example, a third precursor comprisinga nitrogen-containing compound is provided and reacts with the adsorbedprecursor comprising the niobium to form a niobium nitride, therebyintroducing niobium into the transition metal nitride film. This thirdprecursor may also be referred to as a “nitrogen precursor” or “nitrogenreactant.” As described herein, the third precursor may comprise ammonia(NH₃) and/or another suitable nitrogen-containing compound or nitrogenexcited species. The nitrogen precursor of the niobium nitridedeposition sub-cycle may be the same as or different from a nitrogenprecursor of the transition metal nitride deposition sub-cycle.

Additional processes or phases may be added and phases may be removed asdesired to adjust the composition of the final film. In some embodimentsfor depositing a transition metal niobium nitride film, one or moreniobium nitride deposition sub-cycles typically begins with provision ofthe precursor comprising the niobium followed by the nitrogen precursor.In some embodiments, one or more deposition sub-cycles begins withprovision of the nitrogen precursor followed by the precursor comprisingthe niobium. One or more of the precursors of the niobium nitridesub-cycle may be provided with the aid of a carrier gas, such asnitrogen (N₂), Ar and/or He. In some embodiments, the carrier gas maycomprise another inert gas.

FIG. 2 shows a flow chart of an example of a process 200 for forming atransition metal niobium nitride film on a substrate. In someembodiments the process is a thermal ALD process, whereas in otherembodiments the process is a plasma enhanced ALD process. TheALD-process 200 can include a complete deposition cycle 203 having atransition metal nitride sub-cycle 204. As shown in FIG. 2, theALD-process 200 can include a niobium nitride sub-cycle 206 for addingniobium components to the growing transition metal niobium nitride film.In some embodiments, the transition metal nitride sub-cycle 204, niobiumnitride sub-cycle 206, and/or the complete deposition cycle 203 can berepeated a number of times to form a transition metal niobium nitridefilm having a desired composition and/or thickness. The ratio of thetransition metal nitride sub-cycle 204 to the niobium nitride sub-cycle206 can be varied to tune the concentration of niobium in the film andthus to achieve a film with desired characteristics. For example, thenumber of times niobium nitride sub-cycle 206 is repeated relative tothe number of times the transition metal sub-cycle 204 is repeated canbe selected to provide a transition metal nitride film with desiredcharacteristics (e.g., desired electrical resistivity, density, andmechanical properties).

The transition metal nitride sub-cycle 204 can include blocks 208 and210. In block 208, the substrate can be exposed to a first reactantwhich may comprise a transition metal precursor. In block 210, thesubstrate can be exposed to a third reactant which may comprise anitrogen precursor. In some embodiments, the transition metal nitridesub-cycle 204 can be repeated a number of times (e.g., a number ofrepetitions of the blocks 208 followed by 210). In some embodiments,block 208 or block 210 can be repeated a number of times beforeperforming one or more times the other block. For example, block 208 canbe repeated a number of times before performing block 210.

In some embodiments pulses of the transition metal precursor forexposing the substrate to the transition metal precursor and pulses ofnitrogen precursor for exposing the substrate to the nitrogen precursorare separated by a step of removing excess transition metal precursorfrom the reactor (not shown). In some embodiments excess nitrogenprecursor is removed prior to repeating the transition metal nitridesub-cycle 204. In some embodiments, the transition metal nitridesub-cycle 204 is an ALD process. In some embodiments, the pulses of thetransition metal and nitrogen precursor may at least partially overlap.In some embodiments, no additional precursors are provided to thereaction chamber either between blocks 208 and 210, or before startingblocks 208 and 210.

The niobium nitride sub-cycle 206 for introducing a niobium componentinto the transition metal nitride film can include blocks 212 and 214.In block 212, the substrate can be exposed to a second precursorcomprising niobium. In block 214, the substrate can be exposed to anitrogen precursor. In some embodiments, niobium nitride sub-cycle 206can be repeated a number of times. In some embodiments, block 212 orblock 214 can be repeated a number of times before performing one ormore times the other block. For example, block 212 can be repeated anumber of times before performing block 214.

In some embodiments excess nitrogen precursor is removed prior torepeating the niobium nitride sub-cycle 206. In some embodiments, excessprecursor comprising the niobium from block 212 can be removed prior toexposing the substrate to the nitrogen precursor in block 214. In someembodiments, the niobium nitride sub-cycle 206 is an ALD process. Insome embodiments, the pulses of the precursor comprising niobium and ofthe nitrogen precursor may at least partially overlap. In someembodiments, no additional precursors are provided to the reactionchamber either between blocks 212 and 214, or before starting blocks 212and 214.

Once the at least one transition metal nitride sub-cycle and at leastone niobium nitride sub-cycle have been performed the completedeposition cycle 203 may be repeated 216 until a predetermined thicknessof transition metal niobium nitride is achieved 218. When the desiredpredetermined thickness of transition metal niobium nitride is achievedthe complete deposition cycle is terminated and the process may exit220.

In some embodiments, the transition metal nitride sub-cycle 204 mayutilize a first reactant and the first reactant may comprise a metalprecursor, in particular a transition metal precursor. The transitionmetal precursor or compound may comprise at least one of the transitionmetals selected from the group comprising, scandium (Sc), yttrium (Y),titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb),tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), manganese(Mn), technetium (Tc), rhenium (Re), iron (Fe), ruthenium (Ru), osmium(Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium(Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au), zinc (Zn),cadmium (Cd) and mercury (Hg).

As a non-limiting example embodiment, a transition metal halidereactant, such as, e.g., titanium tetrachloride (TiCl₄), may be used asthe transition metal precursor in the ALD processes described herein.

In some embodiments, the transition metal nitride sub-cycle 204 mayutilize a third reactant and the third reactant may comprise a nitrogenprecursor. Methods of the embodiments of the disclosure may compriseselecting the nitrogen precursor to comprise at least one of ammonia(NH₃), ammonia salts, hydrogen azide (HN₃), alkyl derivatives ofhydrogen azide, hydrazine (N₂H₄), hydrazine salts, alkyl derivatives ofhydrazine (e.g., tertbutylhydrazine (C₄H₉N₂H₃), methylhydrazine(CH₃NHNH₂), dimethylhydrazine ((CH₃)₂N₂H₂)), nitrogen fluoride (NF₃) andplasma-excited species of nitrogen (N₂).

In some embodiments, the niobium nitride sub-cycle 206 may utilize asecond reactant and the second reactant may comprise a niobiumprecursor. Methods of the embodiments of the disclosure may compriseselecting the niobium precursor to comprise at least one of niobiumpentachloride (NbCl₅), niobium pentafluoride (NbF₅), niobium pentaboride(NbB₅), niobium pentaiodide (NbI₅) and niobium pentabromide (NbBr₅).

In some embodiments, the niobium nitride sub-cycle 206 may utilize athird reactant and the third reactant may comprise a nitrogen precursor.Methods of the embodiments of the disclosure may comprise selecting thenitrogen precursor to comprise at least one of ammonia (NH₃), ammoniasalts, hydrogen azide (HN₃), alkyl derivatives of hydrogen azide,hydrazine (N₂H₄), hydrazine salts, alkyl derivatives of hydrazine,nitrogen fluoride (NF₃) and plasma-excited species of nitrogen (N₂).

In some embodiments, the ALD-process of process 200 may comprise aplasma enhanced atomic layer deposition (PEALD) process. In suchembodiments the nitrogen precursor may comprise a plasma excited speciesof nitrogen (N₂) or a plasma excited species of any nitrogen containingreactant. In some embodiments the third reactant, e.g., a plasma excitedspecies of nitrogen (N₂), may be supplied to the substrate with theaddition of further plasma excited species, such as plasma excitedspecies of hydrogen (H₂).

In embodiments wherein the ALD-process 200 comprises a plasma enhancedatomic layer deposition process utilizing plasma excited species, thesubstrate temperature during deposition may comprise a temperature ofbetween approximately 250° C. and approximately 400° C. In embodimentswhere in the ALD-process 200 comprises a thermal atomic layer depositionprocess, i.e., an absence of plasma excited species, the substratetemperature during deposition may comprise a temperature of betweenapproximately 350° C. and approximately 450° C.

The deposition rate of the thin film by ALD, which is typicallypresented as Å/pulsing cycle, depends on a number of factors including,for example, on the number of available reactive surface sites or activesites on the surface and bulkiness of the chemisorbing molecules. Insome embodiments, the deposition rate of such films may range from about0.3 to about 5.0 Å/pulsing cycle. In some embodiments, the depositionrate can be about 0.3, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0Å/pulsing cycle.

In some embodiments of the disclosure the ALD processes described hereinmay be utilized for forming a transition metal niobium nitride film on asubstrate. The transition metal niobium nitride film may comprise atleast one of a transition metal selected from the group comprising,scandium (Sc), yttrium (Y), titanium (Ti), zirconium (Zr), hafnium (Hf),vanadium (V), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten(W), manganese (Mn), technetium (Tc), rhenium (Re), iron (Fe), ruthenium(Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni),palladium (Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au), zinc(Zn), cadmium (Cd) and mercury (Hg). In some embodiments, the transitionmetal niobium nitride may comprise at least one of a titanium niobiumnitride, a tantalum niobium nitride and a tungsten niobium nitride.

In non-limiting example embodiments of the disclosure the transitionmetal niobium nitride may comprise a titanium niobium nitride. In someembodiments, methods may comprise forming the tin niobium nitride tohave a Young's modulus of greater than approximately 390 gigapascals. Insome embodiments, methods may comprise forming the titanium niobiumnitride to have a density of greater than approximately 5.4 g/cm³. Insome embodiments, methods may comprise forming the titanium niobiumnitride to have an electrical resistivity of between approximately 200μΩ-cm and approximately 1000 μΩ-cm.

In some embodiments of the disclosure, the transition metal niobiumnitride may comprise a titanium niobium nitride and may have anas-deposited r.m.s. surface roughness (R_(a)) which is less than 8Angstroms, or less than 6 Angstroms, or even less than 4 Angstroms. Ithas been found that the surface roughness of the as-deposited transitionmetal niobium nitride may reduce as the niobium nitride content in thefilm is decreased from 100%, therefore in some embodiments of thedisclosure the methods may involve reducing the surface roughness of thetransition metal niobium nitride by decreasing the niobium nitridecontent in the film. In some embodiments, of the disclosure it was foundthat the minimum in surface roughness of the transition metal niobiumnitride may be found for a niobium nitride sub-cycle percentage of 50%which may correspond to a transition metal niobium nitride film with asurface roughness of less than 4 Angstroms.

The transition metal niobium nitride films, such as titanium niobiumnitride films, formed by the ALD processes disclosed herein can beutilized in a variety of contexts. In one non-limiting exampleembodiment, the transition metal niobium nitride may be utilized in theformation of gate electrode structures. One of skill in the art willrecognize that the processes described herein are applicable to manycontexts, including fabrication of PMOS transistors including planardevices as well as multiple gate transistors, such as FinFETs. Inanother non-limiting example embodiment, the transition metal niobiumnitride may be utilized as an electrode in a DRAM device structure. Inanother non-limiting example embodiment, the transition metal niobiumnitride may be utilized as a barrier material and/or a capping layer inelectrical interconnection applications.

As a non-limiting example, and with reference to FIG. 3, a semiconductordevice structure 300 may comprise a semiconductor body 316 and anelectrode 310 comprising a transition metal niobium nitride disposedover the semiconductor body 316. In more detail, the semiconductordevice structure may comprise a transistor structure and may alsoinclude a source region 302, a drain region 304, and a channel region306 there between. A transistor gate structure 308 may comprise anelectrode 310, i.e., a gate electrode, which may be separated from thechannel region 306 by a gate dielectric 312. According to the teachingof the present disclosure, the gate electrode 310 may comprise atransition metal niobium nitride film, such as titanium niobium nitride,formed by an atomic layer deposition process as described herein. Asshown in FIG. 3, in some embodiment the transistor gate structure 308may further comprise one or more additional conductive layers 314 formedon the gate electrode 310. The one or more additional conductive layers314 may comprise at least one of polysilicon, a refractory metal, atransition metal carbide and a transition metal nitride.

In some embodiments, the semiconductor device structure 300 may comprisea PMOS transistor, the PMOS transistor may further comprise thetransistor gate structure 308. The PMOS transistor gate structure 308may comprise a gate electrode 310 comprising a transition metal niobiumnitride film and a gate dielectric 312 disposed between the transitionmetal nitride film and a semiconductor body 316.

In some embodiments, the gate electrode 310, may comprise a transitionmetal niobium nitride film, such as, for example, titanium niobiumnitride, tantalum niobium nitride, and tungsten niobium nitride. As anon-limiting example of the embodiments of the disclosure, thesemiconductor device structure may comprise a silicon body 316, ahafnium oxide (2 nm) gate dielectric 312 and one of a titanium niobiumnitride (niobium nitride sub-cycle percentage of 50%.), a niobiumnitride, and a titanium nitride as the gate electrode 310. An additionalconductive layer disposed on the gate electrode 310 may compriseplatinum. Table 1 below shows the effective work function measured forthe non-limiting examples for various thickness of the gate electrode310. In some embodiments, the transistor gate structure 308 may comprisea titanium niobium nitride gate electrode and the transistor gatestructure may have an effective work function of greater thanapproximately 4.6 eV, or greater than 4.7 eV, or even greater than 4.85eV

TABLE 1 Gate Electrode TiNbN TiNbN NbN TiN Thickness (nm) 3 10 10 10Effective work 4.60 4.85 4.78 4.80 function (eV)

It should be noted that the embodiments of the disclosure allow forformation of gate electrode structures comprising thin metal niobiumnitrides films with increased effective work function, for example, insome embodiments methods may comprise forming a gate electrode structurecomprising a transition metal niobium nitride gate electrode with athickness of less than 100 Angstroms with an effective work function ofgreater than 4.85 eV. In further embodiments, methods may compriseforming the gate electrode structure comprising a transition metalniobium nitride gate electrode with a thickness of less than 30Angstroms with an effective work function of greater than 4.6 eV.

As a non-limiting example, the transition metal niobium nitride filmcomprising the gate electrode 310 may in some embodiment have athickness of less than 50 Angstroms, or in some embodiments less than 30Angstroms or even in some embodiments less than 20 Angstroms.

In some embodiments of the disclosure, the gate electrode 310 maycomprise a metallic bilayer including a first metallic layer of atransition metal niobium nitride and a second metallic layer, disposedover the first metallic layer at select MOS device locations bypatterning and etching steps, the second metallic layer comprising, forexample, a metal nitride. As a non-limiting example, the bilayermetallic gate electrode 310 may comprise a titanium niobium nitride filmwith a thickness of 10-30 Angstroms and an overlying, adjacent titaniumnitride film with a thickness of 10-30 Angstroms. In some embodiments ofthe disclosure, the transition metal niobium nitride film may act as anetch stop to prevent over etching and protect the underlying gatedielectric. Therefore in some embodiments, the transition metal niobiumnitride may have an etch selectivity, i.e., the relative etching rate ofthe overlying metal nitride film compared with the transition metalniobium nitride film, of greater than 2:1, or greater than 5:1, or evengreater than 10:1. For example, the bilayer metallic gate electrode maybe etched by a combination of wet etch chemistries (e.g., utilizinghydrofluoric acid) and dry etch chemistries (utilizing fluorine basedetch chemistries). In some embodiments of the disclosure, the etch rateof the transition metal niobium nitride was found to increase withdecreasing niobium nitride content, therefore the etch selectivity ofthe transition metal niobium nitride may be tailored for a specificapplication by tuning the composition of the transition metal niobiumnitride. In some embodiments of the disclosure, the etching of themetallic bilayer gate electrode may be performed such that the thicknessof the overlying metal nitride and/or the thickness of the transitionmetal niobium nitride varies across the surface of a substrate (or anintegrated circuit). The variation in thickness of the bilayer metallicgate electrodes results in gate electrodes with different effective workfunctions which consequently may result in a plurality of MOS deviceswith varying threshold voltages, i.e., multi-Vt MOS devices in anintegrated circuit.

As another non-limiting example embodiment, the transition metal niobiumnitride may be utilized as an electrode in a DRAM device structure asillustrated in FIG. 4. In more detail, FIG. 4 illustrates asemiconductor device structure 400 comprising a semiconductor body 402and an electrode 404 comprising a transition metal niobium nitridedisposed over the semiconductor body.

FIG. 4 illustrates a cross-section view of a partially fabricated DRAMdevice structures and the processes for forming such a DRAM devicestructure are described in U.S. Pat. No. 7,910,452 issued to Roh, etal., and incorporated by reference herein. Referring to FIG. 4, aninsulation layer 406 may be formed over a semiconductor body 402 whichcomprises a semi-finished substrate. Storage node contact holes areformed in the insulation layer 406 and storage node contact plugs 408are formed in the storage node contact holes. The insulation layer 406may comprise an undoped silicate glass (USG) and may be formed to athickness ranging from approximately 1,000 Angstroms to approximately3,000 Angstroms. A patterned etch stop layer 410 may be formed over theinsulation layer 406. A conductive layer for forming the storage nodemay comprise an electrode 404 and the electrode 404 may comprise atransition metal niobium nitride and structurally may comprise acylinder type storage node. In some embodiments, the electrode 404 maycomprise at least one of a titanium niobium nitride, a tantalum niobiumnitride and a tungsten niobium nitride.

In non-limiting example embodiments of the disclosure the electrode 404may comprise a titanium niobium nitride. In some embodiments, methodsmay comprise forming the titanium niobium nitride to have a Young'smodulus of greater than approximately 390 gigapascals. In someembodiments, methods may comprise forming the titanium niobium nitrideto have a density of greater than approximately 5.4 g/cm³. In someembodiments, methods may comprise forming the titanium niobium nitrideto have an electrical resistivity of less than approximately 1000 μΩ-cm.

As another non-limiting example embodiment, a transition metal niobiumnitride may be utilized as a barrier material and/or a capping layer ina back-end-of-line (BEOL) metallization application, as illustrate inFIG. 5. In more detail, FIG. 5 illustrates a partially fabricatedsemiconductor device structure 500 comprising, a substrate 502 which maycomprise partially fabricated and/or fabricated semiconductor devicestructures such as transistors and memory elements (not shown). Thepartially fabricated semiconductor device structure 500 may include adielectric material 504 formed over the substrate 502 which may comprisea low dielectric constant material, i.e., a low-k dielectric, such as asilicon containing dielectric or a metal oxide. A trench may be formedin the dielectric material 504 and a barrier material 506 may disposedon the surface of the trench which prevents, or substantially prevents,the diffusion the metal interconnect material 508 into the surroundingdielectric material 504. In some embodiments of the disclosure, thebarrier material 506 may comprise a transition metal niobium nitride,such as, for example, a titanium niobium nitride. In some embodiments ofthe disclosure the transition metal niobium nitride may have a thicknessof less than 35 Angstroms, or 25 Angstroms, or even 15 Angstroms. Not tobe bound by any theory, but it is believed that a transition metalniobium nitride barrier material may be capable of preventing diffusionof the metal interconnect material 508 at a significantly lowerthickness than common barrier materials utilized currently for thefabrication of integrated circuits. The partially fabricatedsemiconductor structure 500 may also comprise a metal interconnectmaterial 508 for electrical interconnecting a plurality of devicestructures disposed in substrate 502. In some embodiments, the metalinterconnect material 508 may comprise one or more of copper, or cobalt.In addition to the use of a transition metal niobium nitride as abarrier material, a transition metal niobium nitride may also beutilized as a capping layer. Therefore, with reference to FIG. 5, thepartially fabricated semiconductor device structure 500 may also includea capping layer 510 disposed directly on the upper surface of the metalinterconnect material 508. The capping layer 510 may be utilized toprevent oxidation of the metal interconnect material 508 and importantlyprevent the diffusion of the metal interconnect material 508 intoadditional dielectric materials formed over the partially fabricatedsemiconductor structure 500 in subsequent fabrication processes, i.e.,for multi-level interconnect structures. In some embodiments of thedisclosure, the capping layer 510 may also comprise a transition metalniobium nitride, such as, for example, titanium niobium nitride with athickness of less than 20 Angstroms, or less than 15 Angstroms, or evenless than 10 Angstroms. In some embodiments, the metal interconnectmaterial 508, the barrier material 506, and the capping layer 510 maycollectively form an electrode for the electrical interconnection of aplurality of semiconductor devices disposed in the substrate 502.

Embodiments of the disclosure may also include a reaction systemconfigured to perform the methods of the disclosure. In more detail,FIG. 6 schematically illustrates a reaction system 600 including areaction chamber 602 that further includes mechanism for retaining asubstrate (not shown) under predetermined pressure, temperature, andambient conditions, and for selectively exposing the substrate tovarious gases. A precursor reactant source 604 may be coupled byconduits or other appropriate means 604A to the reaction chamber 602,and may further couple to a manifold, valve control system, mass flowcontrol system, or mechanism to control a gaseous precursor originatingfrom the precursor reactant source 604. A precursor (not shown) suppliedby the precursor reactant source 604, the reactant (not shown), may beliquid or solid under room temperature and standard atmospheric pressureconditions. Such a precursor may be vaporized within a reactant sourcevacuum vessel, which may be maintained at or above a vaporizingtemperature within a precursor source chamber. In such embodiments, thevaporized precursor may be transported with a carrier gas (e.g., aninactive or inert gas) and then fed into the reaction chamber 602through conduit 604A. In other embodiments, the precursor may be a vaporunder standard conditions. In such embodiments, the precursor does notneed to be vaporized and may not require a carrier gas. For example, inone embodiment the precursor may be stored in a gas cylinder. Thereaction system 600 may also include additional precursor reactantsources, such precursor reactant sources 606 and 608 which may also becoupled to the reaction chamber by conduits 606A and 608A respectively,as described above.

A purge gas source 610 may also be coupled to the reaction chamber 602via conduits 610A, and selectively supplies various inert or noble gasesto the reaction chamber 602 to assist with the removal of precursor gasor waste gases from the reaction chamber. The various inert or noblegases that may be supplied may originate from a solid, liquid or storedgaseous form.

The reaction system 600 of FIG. 6, may also comprise a system operationand control mechanism 612 that provides electronic circuitry andmechanical components to selectively operate valves, manifolds, pumpsand other equipment included in the reaction system 600. Such circuitryand components operate to introduce precursors, purge gases from therespective precursor sources 604, 606, 608 and purge gas source 610. Thesystem operation and control mechanism 612 also controls timing of gaspulse sequences, temperature of the substrate and reaction chamber, andpressure of the reaction chamber and various other operations necessaryto provide proper operation of the reaction system 400. The operationand control mechanism 612 can include control software and electricallyor pneumatically controlled valves to control flow of precursors,reactants and purge gases into and out of the reaction chamber 602. Thecontrol system can include modules such as a software or hardwarecomponent, e.g., a FPGA or ASIC, which performs certain tasks. A modulecan advantageously be configured to reside on the addressable storagemedium of the control system and be configured to execute one or moreprocesses.

In some embodiments, the reaction system 600 of FIG. 6 may comprise aplasma enhanced atomic layer deposition system and may additionalcomprise a plasma generation component which may in some embodiments be“local”, i.e., a component part of the reaction chamber 602, oralternative may in some embodiments be “remote”, i.e., the plasma andassociated plasma excited species are generated remotely from thereaction chamber and subsequently feed to the reaction chamber utilizingappropriate conduits.

Those of skill in the relevant arts appreciate that other configurationsof the present reaction system are possible, including different numberand kind of precursor reactant sources and purge gas sources. Further,such persons will also appreciate that there are many arrangements ofvalves, conduits, precursor sources, purge gas sources that may be usedto accomplish the goal of selectively feeding gasses into reactionchamber 602. Further, as a schematic representation of a reactionsystem, many components have been omitted for simplicity ofillustration, and such components may include, for example, variousvalves, manifolds, purifiers, heaters, containers, vents, and/orbypasses.

The example embodiments of the disclosure described above do not limitthe scope of the invention, since these embodiments are merely examplesof the embodiments of the invention, which is defined by the appendedclaims and their legal equivalents. Any equivalent embodiments areintended to be within the scope of this invention. Indeed, variousmodifications of the disclosure, in addition to those shown anddescribed herein, such as alternative useful combination of the elementsdescribed, may become apparent to those skilled in the art from thedescription. Such modifications and embodiments are also intended tofall within the scope of the appended claims.

What is claimed is:
 1. A method for forming a transition metal niobiumnitride film on a substrate by atomic layer deposition, the methodcomprising: contacting the substrate with a first reactant comprising atransition metal precursor; contacting the substrate with a secondreactant comprising a niobium precursor; and contacting the substratewith a third reactant comprising a nitrogen precursor.
 2. The method ofclaim 1, wherein the method comprises performing at least one depositioncycle in which the substrate is alternatively and sequentially contactedwith the first reactant, the second reactant and the third reactant. 3.The method of claim 2, wherein the deposition cycle is repeated two ormore times.
 4. The method of claim 1, wherein the method comprisesperforming at least one complete deposition cycle, wherein performing atleast one complete deposition cycle comprises: performing at least onetransition metal nitride sub-cycle; and performing at least one niobiumnitride sub-cycle.
 5. The method of claim 4, wherein performing at leastone transition metal nitride sub-cycle further comprises: alternativelyand sequentially contacting the substrate with the first reactant andthe third reactant; and forming a transition metal nitride.
 6. Themethod of claim 4, wherein performing at least one niobium nitridesub-cycle further comprises: alternatively and sequentially contactingthe substrate with the second reactant and the third reactant; andforming a niobium nitride.
 7. The method of claim 1, further comprisingselecting the transition metal precursor to comprise at least one of atitanium precursor, a tantalum precursor and a tungsten precursor. 8.The method of claim 7, further comprising selecting the titaniumprecursor to comprise a titanium halide.
 9. The method of claim 8,further comprising selecting the titanium halide to comprise titaniumtetrachloride (TiCl₄).
 10. The method of claim 1, further comprisingselecting the niobium precursor to comprise at least one of niobiumpentachloride (NbCl₅), niobium pentafluoride (NbF₅), niobium pentaboride(NbB₅), niobium pentaiodide (NbI₅) and niobium pentabromide (NbBr₅). 11.The method of claim 1, further comprising selecting the nitrogenprecursor to comprise at least one of ammonia (NH₃), ammonia salts,hydrogen azide (HN₃), alkyl derivatives of hydrogen azide, hydrazine(N₂H₄), hydrazine salts, alkyl derivatives of hydrazine, nitrogenfluoride (NF₃) and plasma-excited species of nitrogen (N₂).
 12. Themethod of claim 1, wherein contacting the substrate with a thirdreactant further comprises contacting the substrate with aplasma-excited species of hydrogen (H₂).
 13. The method of claim 1,further comprising forming a titanium niobium nitride on the substrate.14. The method of claim 1, further comprising, heating the substrate toa temperature of between approximately 250° C. and approximately 450° C.15. The method of claim 1, further comprising forming the transitionmetal niobium nitride to have a Young's modulus of greater thanapproximately 390 gigapascals.
 16. The method of claim 1, furthercomprising forming the transition metal niobium nitride to have adensity greater than approximately 5.4 g/cm³.
 17. The method of claim 1,further comprising forming the transition metal niobium nitride to havean electrical resistivity of less than approximately 1000 μΩ-cm.
 18. Themethod of claim 1, further comprising forming a gate electrode structurecomprising the transition metal niobium nitride.
 19. The method of claim18, wherein forming the gate electrode structure comprising thetransition metal niobium nitride further comprises, forming the gateelectrode structure having an effective work function greater than 4.6eV.
 20. The method of claim 1, further comprising forming a dynamicrandom access (DRAM) capacitor comprising the transition metal niobiumnitride.
 21. The method of claim 1, further comprising forming a barriermaterial comprising the transition metal niobium nitride.
 22. The methodof claim 1, further comprising forming a capping layer comprising thetransition metal niobium nitride.
 23. The method of claim 1, whereinforming the transition metal niobium nitride further comprises forming ananolaminate structure.
 24. The method of claim 1, wherein thetransition metal niobium nitride has an etch selectivity relative to ametal nitride of greater than 10:1.
 25. The method of claim 1, whereinthe transition metal niobium nitride has a r.m.s. surface roughness(R_(a)) of less than 4 Angstroms.
 26. A reaction system configured toperform the method of claim 1.